I have a 3588 digital tachometer that is giving me problems. Original unit w/ rpm, exhaust temp, 1000 pto, & mph. Seems to be speratic, but at times it won't indicate the proper rpm, mph, etc. Sometimes it reads high, sometimes low, or it flutters up and down w/o changing the motor rpm or tractor speed.

I had a replacement tach unit so I switched it out. Same issues, so it looks like its in the wiring harness? Speed sensor under the seat was replaced a couple of years ago. Does anyone have suggestions or steps for trouble shooting this? I'd like to have this working correctly because its my planter tractor.

Disconnect the engine speed sensor and clean the connector contacts, remove sensor from clutch housing , clean end and then readjust it , turn in until it contacts flywheel ring gear, then back out half to three quarters turn. There is also a inline fuse down by the other fuses, clean those connectors. On the back side of the data center is a pull out module, clean those contacts with a pencil eraser. Check and clean your ground cable on right front cab mount. Then just throw up your hands.

Disconnect the engine speed sensor and clean the connector contacts, remove sensor from clutch housing , clean end and then readjust it , turn in until it contacts flywheel ring gear, then back out half to three quarters turn. There is also a inline fuse down by the other fuses, clean those connectors. On the back side of the data center is a pull out module, clean those contacts with a pencil eraser. Check and clean your ground cable on right front cab mount. Then just throw up your hands.